Radioactive water might have found its way into the Pacific ocean and experts believe it could contain strontium

Large quantities of highly radioactive water have leaked through a crack in the wall of a treatment facility at the Fukushima power plant, and some may have founds its way into the sea, the plant’s operator, Tokyo Electric Power [Tepco], said.

The firm said as much as 45 tonnes of water had leaked through the concrete wall of a building being used to purify contaminated water that is then used to cool molten fuel in the plant’s three damaged reactors.

The firm has piled up sandbags to prevent further leaks but fears some water may have already found its way into a gutter that connects to the Pacific ocean about 600 metres away.

Experts believe the water could contain high levels of strontium-90, a beta-emitting radioactive substance that, if ingested, can cause bone cancer.

Public broadcaster NHK reported that although caesium levels in the leaked water were low, it could contain up to 130,000 becquerels per cubic centimetre of strontium, which has a half-life of 29 years.

Workers temporarily halted the purification apparatus after spotting a puddle of water on Sunday. They later recorded 1.8 millisieverts [mSv] per hour of gamma radiation and 110mSv per hour of beta radiation on the surface of the puddle, the company said in a statement.

It said the leak appeared to have been stemmed, adding it already had enough purified water to continue cooling the reactors as scheduled.

The discovery underlines the difficulties facing Fukushima Daiichi workers as they struggle to contain and reuse large volumes of contaminated water.

In October, the Institute for Radiological Protection and Nuclear Safety, a French government body, said the plant had been responsible for the biggest-ever discharge of radioactive material into the sea.

More details have emerged, meanwhile, of the workers’ desperate struggle to save the power plant in the moments after it was struck by a tsunami of up to 14 metres in height on the afternoon of 11 March.

One of the unnamed employees, who was in charge of the main control room at the time of the disaster, recalled how, at one point, he had begged colleagues not to abandon the plant.

He realised that the tsunami had caused a disaster when the lights on the plant’s control panels flickered, and then went out. “I came to realise that a tsunami had hit the site when one of the workers came rushing into the control room, shouting ‘Sea water is gushing in!'” he said. “I felt at a complete loss after the power went down.”

He said the plant’s “anxious” employees argued over how to contain the crisis, with one suggesting they had no choice but to flee. “He said: ‘Is there any point in staying when there is nothing we can do?’

“I bowed my head and begged them to stay.”

Workers at the site in the aftermath of the accident – quickly nicknamed the Fukushima 50 because they initially worked in groups of around that number – have been hailed as heroes for remaining at their posts and preventing an even greater catastrophe.

One recalled how he had volunteered to enter a reactor building to manually open a ventilation valve in an attempt to ease the pressure building inside.

“We put on full protective gear, but we couldn’t possibly let younger workers do that job as we were entering an area with high levels of radiation,” he said.

“When I got there, I heard a strange, loud popping sound from below, and when I tried to start work, my black rubber boots melted [due to the heat].”

The workers echoed fears voiced recently by the plant’s chief, Masao Yoshida, who has taken early retirement due to an unspecified illness, that there were moments when they believed they would die.

“We experienced big aftershocks and had to keep fleeing [from possible tsunami] up the hill still wearing our protective masks,” said one worker.

Another recalled how he and his colleagues constantly worried about being electrocuted as they worked while standing in puddles of water.

… these are not “dosimeters” but “glass badges” that passively collect radiation information. It won’t help these children or their parents to avoid high-radiation areas and spots, it won’t tell them how much radiation they will have been exposed unless they are sent in to a company to interpret the data.

Radiation exposure is increased by a factor of a trillion. Inhaling even the tiniest particle, that’s the danger.

Yo: So making comparisons with X-rays and CT scans has no meaning. Because you can breathe in radioactive material.

Hirose: That’s right. When it enters your body, there’s no telling where it will go. The biggest danger is women, especially pregnant women, and little children. Now they’re talking about iodine and cesium, but that’s only part of it, they’re not using the proper detection instruments. What they call monitoring means only measuring the amount of radiation in the air. Their instruments don’t eat. What they measure has no connection with the amount of radioactive material.

Dr. Helen Caldicott (Co-founder of Physicians for Social Responsibility):

You’ve bought the propaganda from the nuclear industry. They say it’s low-level radiation. That’s absolute rubbish. If you inhale a millionth of a gram of plutonium, the surrounding cells receive a very, very high dose. Most die within that area, because it’s an alpha emitter. The cells on the periphery remain viable. They mutate, and the regulatory genes are damaged. Years later, that person develops cancer. Now, that’s true for radioactive iodine, that goes to the thyroid; cesium-137, that goes to the brain and muscles; strontium-90 goes to bone, causing bone cancer and leukemia. It’s imperative … that you understand internal emitters and radiation, and it’s not low level to the cells that are exposed. Radiobiology is imperative to understand these days.”